Method and apparatus for shaping and sizing dentures



1962 c. N. SKINNER 3,049,804

METHOD AND APPARATUS FOR SHAPING AND SIZING DENTURES Filed Feb. 24, 1959 2 Sheets-Sheet 1 IN V EN TOR. CLAWSO/V M SK/A/A/E/Q Aug. 21, 1962 c. N. SKINNER METHOD AND APPARATUS FOR SHAPING AND SIZING DENTURES Filed Feb. 24, 1959 2 Sheets-Sheet 2 INVENTOR. CLAIM/SON M .SK/NA/EE BY 4 /7 a: a EA/EX 3,049,804 METHOD AND APPARATUS FOR SHAPING AND SllZING DENTURES Clawson N. Skinner, 2108 Elray Drive, Whittier, Calif. Filed Feb. 24, 1959, Ser. No. 794,999

11 Claims. (Cl. 32-1) This invention relates to the fitting of dentures and more particularly to an improved method, technique and apparatus for shaping and sizing dentures in such manner that the finished article will be in harmony with the physiognomy of the patient.

It has long been an established scientific fact that the size and shape of the maxillary incisors bear a remarkably close resemblance to that of the individuals face 5 and, in the great majority of cases, differ from the measurements thereof in the ratio of l to 16. Stated differently, the shape, contour and dimensions of the maxillary incisors differ from those of the individuals face in the ratio of l to 16, the tooth measurements being inverted to those of the face. The generally horizontal hair line across the forehead a viewed from a vantage point directly forward of the face corresponds to the biting edge of the incisors; the outline of the face below the described hair line corresponds to the frontal outline of the tooth, and the front curvature of the tooth corresponds to a profile curvature taken along a median plane through the face, the opposite ends of the curve being based on the top at the frontal hair line and on the 3 mask or overlay on a slightly oversized denture. Suitable dye or other marking material is then applied, as will be described in detail below, in grinding the tooth accurately to shape and size.

As a further aid in obtaining the patients facial image notwithstanding the wide differing hair dress, resort is preferably had to a framing device comprising a plurality of legs or arms adjustably secured together and adapted to embrace the top of the head with portions extending across the top edge of the forehead and along either side of the face in a manner masking the ears and the hair and framing the more prominent outline features of the face.

Accordingly, it i a primary object of the present invention to provide an improved technique and apparatus for shaping and sizing replacement dentures for the maxillary incisors utilizing as a guide the patients own facial dimensions and general contours.

Another object of the invention is the provision of an optical method of reducing certain facial features and dimensions of a dental patient by a ratio of 16 to 1 and utilizing these in accurately and precisely sizing and shaping dentures for that patient.

Another object of the invention isthe provision of an improved method of making replacement dentures for the maxillary incisors which includes optically reducing the patients facial outline in a ratio known to represent the size and shape of these teeth for that person, using the facial outline so obtained as a guide in appropriately marking replacement dentures undergoing processing and 0 finish-processing the denture by the information so ob- I often the case. However, previous proposals for utilizing M the facial measurements have been cumbersome, lacking in the desired accuracy and otherwise deficient in various respects. By some of these prior proposals, attempts have been made to classify the facial types and sizes to the end that classified sets of charts portraying typical faces can be used as a guide in selecting and shaping replacement dentures. Such methods leave much to the judgment of the dentist and understandably have not enjoyed general acceptance by dentists.

Accordingly, a main purpose of this invention is to provide equipment obviating the shortcomings of prior proposals and to provide simple, easily and quickly executed technique employing a minimum of equipment for shaping and sizing of maxillary incisors harmonious to the patients physiognomy. Thus, the present invention proposes the use of conventional optical lense in cornbination with a screen or light sensitive film in a manner providing the dentist with an image of the patients frontal outline and profile accurately registered on the film or screen and accurately reduced by a ratio of 16 to 1. In this manner, the resultant image is precisely reduced to the size of the missing upper incisors. This image is then used as a guide in shaping previously cast dentures to true size and shape for that particular individual.

The technique and apparatus provided by this invention further contemplates the use of either a reflex camera or a self-developing type camera for maximum convenience in obtaining accurately reduced facial images. If a selfdeveloping camera i employed, an image of the patients face is automatically reproduced on film. If a reflex camera is used the facial image may be traced directly on a translucent screen for immediate use as a mask or a guide in preparing the replacement denture. In either case, the outline obtained can be cut out by the use of a scalpel or other sharp pointed blade in order that either the cut-out itself or the resultant frame may be used as a tained.

Another object of the invention is the provision of an adjustable framing device adapted to be mounted crosswise of the patients head in a manner concealing major portions of the hair and ears and aiding the dentist in obtaining a frontal facial outline as well as a side profile view of the patient for use in making dentures in harmony with the physiognomy of the patient.

These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawings to which they relate.

Referring now to the drawings in which preferred embodiments of the invention are illustrated:

FIGURE 1 is a schematic perspective view of the apparatus of this invention in position for taking accurate scale frontal and profile images of a patients face;

FIGURE 2 is an enlarged frontal view of the patient shown in FIGURE 1 and more particularly of the framing device used as an aid in obtaining an outline of the patients face;

FIGURE 3 is a side View corresponding to FIGURE 2 with portions broken away to show construction details;

FIGURE 4 is a schematic perspective view on a reduced scale similar to FIGURE 1 but showing reflex type cameras substituted for the self-developing film type employed in the FIGURE 1 embodiment;

FIGURE 5 is a view showing the film screen obtained by the use of apparatus shown in FIGURES 1 and 4 formed into a mask overlying an artificial denture while dye is being sprayed onto the front surface of the denture;

FIGURE 6 is a view of the denture after being sprayed; and

FIGURE 7 is a view generally similar to FIGURE 5 showing how the tracing obtained as shown in FIGURE 4- is cut away to form a mask or a guide in grinding the front surface of the tooth to shape.

Referring first to FIGURES 1 and 2 showing apparatus for practicing the invention according to one preferred embodiment thereof, the dentist makes use of a camera 10 having built-in film developing equipment of a well known type, the camera being suitably supported as on a tripod, not shown. The camera is so positioned that its optical axis 11 is aligned with the center of the patients face. The focal distance of the lens in the camera shown in FIGURE 1 is such that a one-sixteenth scale image of the patients face will be obtained on the film when the camera lens is spaced seven feet, four inches from a plane representing the patients facial contour as viewed by the camera lens. It will be understood that the focal length of any particular camera lens must be so related to the spacing of the lens from the patient that the resultant image is one-sixteenth the size of the subject.

To facilitate taking the facial outline image, the dentist preferably employs a framing device designated generally 12. This device comprises a plurality of elongated strips of any suitable lightweight material such as aluminum, stilf plastic or the like, including a T-shaped member 13, a pair of similar strips 14 and 15 and a second smaller T-shaped member made up of strips 17 and 18 adjustably secured together opposite slot 19 by a thumb screw clamp 20. Both T-shaped assemblies are inverted and the upper ends of their legs 18, 21 are interconnected by a spacer 23. The structural details of spacer 23 are best shown in FIG- URE 3 from which it will be observed that one end of its shank includes a spherical-shaped enlargement 24' seating in a socket 25 formed in the upper end of leg 21 of T- shaped member 13. Extending through the bottom of socket 25 is a large diameter opening 26 adjustably seating the threaded shank end 24 of spacer 23. The ball and socket joint thus provided is held in any desired adjusted position by means of a semi-spherical washer 27 and a thumb nut 28 threaded over shank 24. Vertical leg 18 of the smaller T-shaped framing element is rigidly anchored to the forward end of spacer 23, as by a cap screw 30.

The longer end of the head of T-shaped member 13 is formed with an elongated slot 31 adjustably Supporting therein vertical leg 15 of the framing device, the latter being clamped in any adjusted position therealong by means of the thumb nut clamp 32. The second vertical leg 14 of the framing device is pivotally connected to the opposite end of T-shaped member 13 by a similar nut and thumb screw clamp 33.

The described apparatus is used as follows in preparing a replacement maxilla incisor for a particular patient. The main body portion of framing device 12 is first adjusted and properly installed on the patients head in a generally vertical plane transversely of the head and slightly forward of the ear and best illustrated in FIG- URE 3. In this position head 17 of the smaller T-shaped member rests against the top of the forehead at the base of the hair line and aids in the support of the framing device. Further assistance for this purpose is provided by the two vertical strips 14 and 15' which areradjusted to engage the opposite sides of the face under slight pressure, this adjustment being facilitatedby the thumb screws 32, 33 and slot 31. The adjustment of the smaller T-member is facilitated by the ball and socket 24, 25 associated with thumb screw 28. Further adjustment is provided by slot 19 and thumb screw 20 interconnecting vertical strip 18 and horizontal strip 17.

It is pointed out that when framing device 12 is properly positioned, as described, the lower edge of'strip 17 represents the biting edge of the maxilla incisor. The remainder of the maxilla incisor tooth outline, as viewed from the front, is represented by the facial outline generally indicated in part in FIGURE 2. by the dot and dash line 35, it being understood that the described outline of the tooth so represented is inverted with respect to its true position on the maxillary alveolar ridge. In other words, the biting edge is represented by the lower edge of strip 17 and the gum line is represented by the rounded contour of the patients chin.

All adjustments of the framing device having been made, the dentist takes an image of the face on film with which camera 10 has been loaded. This film is immediately developed in known manner and removed from the camera, the subjects facial outline then being accurately reduced to one-sixteenth size and truly representing the outline of the maxilla incisor for that particular pat ent.

At this point it is desired to point out that the described dimensional ratio relationship of 16 to 1 between the average face and the closely-spaced teeth normally associated therewith is subject to easily observed variants. For example, teeth are sometimes found which are spaced apart appreciably while still other cases are observed in which the teeth are so crowded as to overlap one another to some degree. Such variants from normal are usually accompanied by similar variants from the described size ratio of 16 to 1. For example, in the case of spaced apart teeth, larger facial features and dimensions are typically present but the teeth are only slightly, if any, larger. Thus, in the case of spaced apart teeth, the facial to tooth dimensions are found to range between 16 and 18 to l, the proper specific ratio within this range being readily recognized and estimated by the dentist exerienced in using the technique and principles of the present invention.

Likewise, in the case of crowded and overlapping teeth, the proper dimensional ratios range between 14 and 16 to 1, the variation from the normal ratio of 16 to 1 being closely correlated with the degree of crowding and overlapping observed. Accordingly, it is to be understood that all references in this specification and in the accompanying claims to the specific ratio of 16 to l are to be read with the foregoing factors and variants in mind.

The next step is to obtain a true scale image of the vertical curvature of the maxilla incisor as viewed from one lateral edge. This curvature is obtained by having the patient turn his head 90 degrees relative to the camera, or alternatively, by moving camera 10 to the position indicated at 10 in FIGURE 1, care being exercised to have the camera lens located at the proper distance from a vertical plane passing centrally through the patients head. With the camera lens here used, this distance is seven feet, four inches. The curve represented by arcuate line 36 and representing the general profile curve of the patients face provides a remarkably true representation of the true frontal curvature of that persons maxilla incisor. The described curved line 36 has its upper end based at the junction of the patients hair line and the upper transverse rim of the forehead and its lower end based at the lower corner of the chin.

The dentist then proceeds as diagrammatically represented in FIGURES S to 7 to form a mask from the developed film using the images obtained as described above in order that the masks can be employed to mark somewhat oversize replacement maxilla incisor dentures.

' One preferred technique is illustrated in FIGURES 5 and 6 wherein 38 represents a developed film carrying the frontal image of the patients face accurately reduced to one-sixteenth size. The closed line 39 represents the outline of the patients face after the face itself has been cut away along this line by a scalpel or other sharp pointed knife. Usually one side of the face is straighter than the other and this side represents the edge of the tooth facing a central plane through the mouth. The straight lower edge 40 of the cutout represents the biting edge whereas the arched opposite end 41 represents the gum line contour. The mask so formed from film 38 is then placed against the front face of a slightly larger denture 42 and a colored dye 43 is sprayed or brushed onto its front face, as by a suitable atomizer nozzle 45, a brush or the like. It will be understood that denture 42 is here shown considerably larger than the mask cutout merely for the purposes of clarity and convenience in illustrating this phase of the technique. In practice, a denture blank would be selected only slightly larger than the mask cutout in order to minimize the grinding and finishing operations. After the mask 38 has been removed, the tinted or colored area 46 representing the shape of the tooth appears as in FIGURE 6.

strip 48 having impressed thereon a profile image of the subject indicated by dot and dash line 50 is formed into a mask described above in connection with strip 38. For example, the curvature of the patients face, and represented by dot and dash line 36, is marked out on film strip 48 as is indicated by curved line 36'. A portion of the film immediately to the right of curved line 36, as viewed in FIGURE 7, is cut out to form a window or opening useful in checking the front curvature of the denture as grinding proceeds. Some dentists prefer to cut away all of the film to the right of curve 36' and then use this curve as a template in checking the grinding work on the front face of the denture.

In another mode of use of film and particularly of strip 38, all portions of the film except the portion inside the image are discarded. In this event the image area is employed as an overlay on the denture to guide grinding or the application of a dye.

Referring to FIGURE 4, there is shown the manner in which a reflex type camera is employed to obtain facial image outlines directly on a heavy grade tracing paper or the like translucent material without need for using photo sensitive film. The procedure followed is exactly the same as described above in connection with FIGURE 1, the only change being the use of a reflex camera 50, 50 in lieu of the self-developing film camera it], In the particular instance illustrated, the reflex camera used has a shorter focal length with the result that its lens is required to be spaced three feet, zero inches to obtain an image on the translucent screens 51, 51' one-sixteenth the subjects facial dimensions. Translucent screen 51 is positioned over the reflex viewing screen and is preferably sized to fit within the usual light shield or hood 52.

The mode of use of the reflex camera is generally similar to that described above in connection with FIG- URE 1 except that a sharp pencil or other writing instrument is used to trace an outline of the face directly on the screen 51, this outline being indicated at 53 and corresponding to the outline 39 in FIGURE 5. A similar outline of the patients profile is traced on the screen 51'. Thereafter the dentist uses the scalpel to cut out along the outline 53 to provide a mask corresponding to mask 38 in FIGURE 5 and through which a coloring agent can be applied to the front surface of a denture to serve as a guide in cutting the same accurately to size and shape.

Some dentists find the use of a dye or coloring agent quite unnecessary when shaping the lateral edges or the frontal surface contour of the denture, preferring instead to employ the film or tracing as a template applied to the denture periodically to check progress of the finish grinding operation. Guide surface 36' in particular is most conveniently used as a template in checking the frontal contour of the denture.

It is also pointed out that the shaping of the frontal surface of incisor dentures in the manner described is found most effective in supporting the upper lip of the patient in its normal and natural position thereby avoiding the likelihood of any undesirable change in the facial expression and appearance of the face following installation of dentures.

While the particular method and apparatus for shaping and sizing dentures herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

I claim:

1. That improvement in the formation of individual dentures to shape .and size which comprises directly forming a frontal image of the patients face on sheet material to a scale approximately one-sixteenth the dimensions of the subject and utilizing the outline shape of the facial image so obtained to and including the forehead to approximately the base of the normal hair line to determine the size and frontal shape of replacement maxillary incisor dentures for that patient.

2. That improvement in the formation of individual dentures to shape and size for individual patients which comprises, masking the hair and ears of the patient as viewed from a point directly forwardly of the patient, taking a frontal photo image of the masked face onesixteenth the size thereof, and utilizing this image as a guide in shaping a maxillary incisor denture for that patient.

3. That improvement defined in claim 2 chaarcterized in the use of optical lens means to focus an outline image of the patients face on a translucent medium, tracing said outline on said translucent medium and subsequently utilizing said traced outline as a guide in grinding to shape and size a replacement maxillary incisor denture for the patient.

4. That mode of shaping and sizing a replacement incisor denture for .a patient which comprises, utilizing optical lens means positioned sufiiciently forwardly of the patients face and of a type effective to cast an outline image of the patients face on an interception screen which image is one-sixteenth the size of su'bjects facial dimensions, reproducing said image outline on said screen, cutting away the portion of the screen lying within said image outline, registering said outline over a slightly oversize blank tooth and utilizing the same as a mask while applying dye to the tooth surface confined to an area in registry with said cutoff, and thereafter grinding away the portion of the tooth outside the dyed area.

5. That mode of shaping and sizing dentures for a patient which comprises utilizing optical lens means to cast a profile image of the patients face on an interception screen which image is one-sixteenth the size of the facial dimensions represented by said image, reproducing said image on said screen and including a curved line to represent the face which curved line has its end points respectively based at the forehead hair line and at the forward lower edge of the chin and is curved therebetween in a manner generally representative of the facial curvature as viewed in profile, and utilizing the resulting curved line as a guide in grinding the frontal profile curve of a maxillary incisor tooth.

6. Framing apparatus adapted to facilitate framing a patients face while making facial contour outlines for use in shaping and sizing dentures properly shaped for a specific person, said apparatus comprising an inverted T-shaped frame having first and second spaced apart legs projecting downwardly substantially at right angles to the head portion thereof, at least one of said legs being adjustable lengthwise of the head portion of said T-shaped frame, a second inverted T-shaped assembly including means adjustably supported from the stern portion of said T-shaped frame, said second T-shaped assembly lying in a plane spaced to one side of a plane passing through said firs-t mentioned T-shaped frame, said framing apparatus being adapted to be arranged about a dental patients face with said T-shaped frame resting against the top of the head and with said first and second legs extending downwardly forwardly of the ears, and said second T-shaped assembly adapted to be positioned with its lower edge extending horizontally across the forehead at approximately the hair line.

7. Apparatus as defined in claim 6 characterized in that said second T-shaped assembly has a universal clamp connection with said T-shaped frame to facilitate adjustment thereof.

8. Apparatus as defined in claim 6 characterized in that the principal components thereof are formed of lightweight rigid strip material and including a plurality of thumb-nut clamping devices for adjnstably clamping said components together in a unitary assembly.

9. A framing device for use in concealing the hair and ears of a dental patient while obtaining an outline image of his face as an aid in the shaping of dentures harmonious with his physiognomy, said device comprising a main frame having a pair of rigid vertical strips including means for adjustably and pivotally supporting said strips near the opposite ends of an intervening cross member adapted to rest crosswise of the patients head, such strips being adjustable in a vertical plane to bring their inner edges into contact with the opposite sides of the patients face close to but forwardly of his ears, said strips being shiftable toward and away from one another as well as pivotable in a vertical plane about their respective points of connection with the cross members of said main frame, and a supplemental member of inverted T-shape including means adjustably supporting the same from said main frame and forwardly thereof with the lower edge of the head portion thereof extending horizontally across the forehead adjacent its merger with the hairline.

10. A framing device as defined in claim 9 characterized in that said main frame and said supplemental mem- 3 bers include adjustable connections between the components thereof to facilitate fitting said framing device to the head of the patient.

11. That mode of determining the shape and size of a replacement incisor denture for a patient which comprises, utilizing optical lens means positioned sufiiciently forwardly of the patients face as to cast an outline image of the face on an interception screen which image is approximately 55 the size of the subjects facial dimensions, reproducing said image outline on said screen and cutting away the portion of the screen lying entirely to one side of said image outline to provide a mask corresponding in size and shape to the size and shape of a replacement incisor denture suitable for that patient.

References Cited in the file of this patent UNITED STATES PATENTS 709,834 Vanderpool Sept. 23, 1902 1,378,745 Wavrin May 17, 1921 1,566,661 Essig Dec. 22, 1925 1,596,458 Schiesari Aug. 17,1926 2,524,542 Roux Oct. 3, 1950 2,752,689 Adams et al. July 3, 1956 

